どちらでも可能ですよ。申請後入国の方がスムーズだと思いますけれど。
カナダ大使館のサイトにこんな風にかかれています。
Question: Can I visit Canada during the processing of the application or, if I already submitted my application, can I go to Canada and wait for my visa there?
Answer: Yes, you can. You will be subject to requirements applicable to visitors. You will normally be granted a stay of six months upon arrival in Canada. This can be extended for another six months. When your visa is ready the visa office will contact you. If your application for immigration is not finalised before the end of your authorized period of stay you will be required to leave Canada.
http://www.canadanet.or.jp/i_v/im/fcqa_e.shtml